Compound resonance unit



July 4, 1939. E. E. WILSON 2,164,365

COMPOUND RESONANCE UNIT Original Filed Jan. 30, 1933 2 sheets sheet 1 gwvmtoz July 4, 1939. E4 5 w so I 2,164,365

COMPOUND RESONANCE UNIT Original Filed Jan. 30, 1933 2 Sheets-Sheet 2 ifs mlllll Patented July 4, 1939 UNITED STATES COMPOUND RESONANCE UNIT Ernest E. Wilson,-Huntington Woods, Mich, as-

signor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application January 30, 1933, Serial No. 654,296 Renewed June 11, 1936 Claims.

This invention has to do with resonance units of the type disclosed in my copending application Serial No. 470,700, filed July 25, 1930 of which this application is, in part, a continuation. In the 5 main this application is concerned with certain embodiments or features of the invention disclosed but not claimed in the above identified application or in my copending application Serial No. 633,265, filed September 15, 1932 which is also,

in part, a continuation of application Serial No. 470,700.

For a better understanding of the nature, ob- J'ects and scope of the invention with which this application is concerned, reference is made to the following specification in which there are described the several embodiments of the invention which are illustrated in the accompanying drawings.

In the accompanying drawings:

Figure 1 is a side elevation of an internal combustion engine on which there are installed intake and exhaust silencers in which are incorporated resonance units in which the invention with which this application is concerned is embodied.

Figure 2 is a central longitudinal section through the silencer installed on the intake tube of the carburetor of the engine illustrated in ,Figure 1.

Figure 3 is a central longitudinal section through the silencer installed on the exhaust pipe of the engine illustrated in Figure 1.

Figures 4, 5 and 6 are central longitudinal sections through modified forms of silencers in which the invention with which this application is concerned is embodied.

In Figures 1, 2 and 3 of the drawings, the reference character 10 indicates an internal combustion engine on which there is provided a carburetor II which is connected to the cylinders of o the engine by an intake manifold l2 and on which there is provided an air intake tube l3, and the reference character l4 the exhaust pipe of the engine which is connected to the cylinders of the engine byan exhaust manifold l5. To the air 5 intake tube of the carburetor and to the exhaust pipe, there are connected silencers l6 and 51, respectively, in which are incorporated resonance units of the type with which this application is concerned. 50 The silencer l6, which is shown in Figures 1 and 2 of the drawings, includes a cylindrical shell l'l over whose opposite ends there are secured heads I8 and I9 and which is subdivided longitudinallyinto two compartments 20 and 2| by an 55 annular partition 22 whose outer edge is circumferentially secured to the shell l'l. Through the central opening in the partition 22, there extends from the compartment 20 into the compartment 2| a tube 23 which is circumferentially secured to the inner edge of the partition 22 and on whose 5 end which is located within the compartment 20 there is provided a perforated annular flange 24 Whose outer edge is circumferentially secured to the shell l'l. In the head I9, there is provided a central opening of larger diameter than that in 10 the partition 22 through which there extends into the shell I! a tube 25 of larger diameter than the tube 23 whose inner end surrounds and is circumferentially spaced from the adjacent end of the tube 23. 15

Through the side wall of the shell I1, there extend into the compartment 20 an annular series of openings 26 through which air may pass from the atmosphere into the tube 23. The end walls l8 and 22 of the compartment 20 are lined with 20 bodies of sound absorbing material which are held against the walls by the element 21 and by the flange 24, respectively. Each of the bodies of sound absorbing material preferably consists of a mat of hair felt 28 covered by a layer of bur- 25 lapor other porous fabric 29 secured to the mat during the felting operation, or by punching, or by an adhesive, but may be constructed of any other suitable material or combinations of materials.

The interior of the compartment 2| is divided into a primary resonance chamber 30 and two secondary resonance chambers 3| and 32 by an annular partition 33 whose outer and inner edges are circumferentially secured to the shell I! and the tube 23, respectively, and an annular partition 34 whose outer and inner edges are circumferentially secured to the shell I! and the tube 25, respectively. Communication between the secondary resonance chambers 3| and 32 and the primary resonance chamber 30 is established by tubes 35 and 36 which extend through openings in, and are circumferentially secured to, the partitions 33 and 34, respectively.

As shown in Figure 1 of the drawings, the silencer I6 is adapted to be installed on the air intake tube of the carburetor of an internal combustion engine by inserting one end of the tube 25 into the carburetor air intake tube and suitably securing it thereto. When the silencer is so installed and the engine is operating, the suction created by the cylinders on their suction strokes, will draw air through the openings 26, into the compartment 2!! and, thence, into the tube 23, whence it will pass through the tube 25, the carburetor and the intake manifold into the cylinders of the engine. Since, as is apparent from the drawings, there is an unobstructed path'through the silencer into the air intake tube of the carburetor, the silencer will offer practically no resistance to the passage of air therethrough.

The resonance unit (which consists of the resonance chambers 38, 3| and 32, the passages which interconnect them and the passage which interconnects the primary resonance chamber 30 and the main passage 2325) of the silencer I 6 is so proportioned and dimensioned in the manner set forth in my co-pending application Serial No. 470,700 and the corresponding foreign patents, viz., Canadian Patent No. 348,037, British Patent No. 391,180, French Patent No. 720,611 and Italian Patent No. 300,037, that it will respond to and attenuate the objectionable sound waves of relatively low frequency which are ordi narily transmitted through the intake manifold and carburetor of the engine to the atmosphere. The objectionable sound waves of relatively high frequency which are ordinarily transmitted through the intake manifold and carburetor of the engine to the atmosphere are attenuated by the bodies of sound absorbing material with which the compartment 20 is lined. Thus, by their conjoint action, the resonance unit and the sound absorbing material effectually attenuate all of the objectionable sound waves which are ordinarily transmitted through the intake manifold and carburetor of the engine to the atmosphere and eliminate the so-called intake noises which are ordinarily found in internatcombustion engines.

To illustrate some of the many forms which resonance units in which the invention with which this application is concerned is embodied may assume, I have included in the drawings Figures 3 to 6, inclusive. It is to be understood that the structures illustrated in Figures 3 to 6 of the drawings, as well as those shown in Figures 1 and 2, may be modified in many ways as to details of construction and that modified structural features shown in any of the figures may be incorporated in the resonance units shown in any other or others of the figures.

The resonance unit which is shown in Figure 3 of the drawings includes a shell 40 over whose opposite ends there are secured heads 4| and 42. Through the heads and the interior of the shell, there extends a tube 43, which, through its projecting end 44, is adapted to be connected to the air intake tube of a carburetor so asto form an extension thereof. The space between the shell 48 and the tube 43 is divided by partitions 45, 46 and 41 into resonance chambers 48, 49, 50 and 5! of which the resonance chambers 48 and 58 are directly connected to the interior of the tube 43 by tubes 52 and 53, respectively. The resonance chambers 48 and 49 are interconnected by a tube 54 which extends through the partition 45. the resonance chambers 49 and 58 by a tube 55 which extends through the partition 46 and the resonance chambers 58 and 5| by a tube 59 which extends through the partition 41. By reason of the fact that they are interconnected as described above and the fact that the resonance chamber 48 is directly connected to the interior of the tube 43, the resonance chambers 48, 49, 50 and 5| may be considered, respectively, primary, secondary, tertiary and quaternary resonance chambers. By reason of the fact that they are interconnected as described above and the fact that the resonance chamber 50 is directlymonnected to the interior of the tube 43, the resonance chambers 48, 49, 58 and 5! may be considered, respectively, tertiary, secondary, primary and secondary resonance chambers. In view of what was said in the sentence next preceding this, it will be apparent that, the resonance unit shown in Figure 3 is the equivalent of a resonance unit of the type shown in Figure 2 plus a resonance chamber directly connected to the passage 2325 and one of the resonance chambers 3| and 32.

The resonance unit which is shown in Figure 4 of the drawings includes a shell 60 over whose opposite ends there are secured heads BI and 62. Through the heads and the interior of the shell there extends a tube 63, which through its projecting end 54, is adapted to be connected to the air intake tube of a carburetor so as to form an extension thereof. The space between the shell 80 and the tube 63 is divided by partitions 65, 66 and 8? into resonance chambers 68, 69, I8 and H of which the resonance chamber 68 is directly connected to the interior of the tube 63 by a tube I2. The resonance chamber 68 is directly connected to the resonance chambers 69, 78 and H by tubes i3, 74 and i5 which extend through the partition 65, the partitions 85 and 66 and the partitions 65, 66 and 57. respectively. The resonance chamber 69 is directly connected to the resonance chambers 79 and H by tubes 16 and 77 which extend through the partition 66 and the partitions 66 and 67. respectively. The resonance chamber i is directly connected to the resonance chamber H by a tube 78 which extends through the partition 57. While the resonance chamber 68 can be considered only as a primary resonance chamber, the resonance chambers 69. 18 and H. by virtue of the fact that each is connected directly to the other and to the primary resonance chamber 68. can be considered as secondary. tertiary or quaternary resonance chambers. In view of what was said in the sentence next preceding this. it will be ap arent that the resonance unit shown in Figure 4 is the equivalent of a resonance unit of the type shown in Figure 2 in which the secondary chambers 3| and 32 are directly interconnected and to which there has been added a resonance chamber d rectlv connected to each of the chambers 30. 3| and 32. Obviously one or more of the tubes I3, 14, 15, I8. 11 and I8 may be omitted and the characteristics of the resonance unit shown in Fi ure 4 thus modified.

The resonance unit which is shown in Figure of the drawings includes a shell 80 over whose opnosi e ends there are secured heads 8| and 82. Throu h the heads and the interior of the shell, there extends a tube 83. which throu h its pro- .ie'ctin end 84. is adapted to be connect d to the air intake tube.- of a carburetor so as to form an extens on thereof. The space between the shell 8" and the tube 83 is divided by partit ons 85 and 86 into resonance chambers 87. 88 and 89 of wh ch the resonance chamber 88 is directly connected to the interior of the tube 83 by a tube 90. Each of the resonance chambers 87 and 89 is 7 directly connected to the resonancechamber 88.

the former by a tube 9! which extends through the partition 85 and the latter by a tube 92 which extends through the partition 86. The resonance chambers 8'1 and 89 are directly interconnected by a tube 93 which extends through the partitions 85 and 86 and to whose intermediate portion there the atmosphere. While the resonance chamber 88 can be considered only as a primary resonance chamber, the resonance chambers 81 and 89, by virtue of the fact that each is directly connected to the other and to the primary resonance chamber, can be considered as either secondary or tertiary resonance chambers. It will be obvious that the tube 93 and/or the tube 94 may be om tted and that if both are omitted, the resonance unit shown in Figure 5 will be equivalent to a resonance unit of the type shown in Figure 2.

The resonance unit which is shown in Figure 6 of the drawings includes a tube I which is adapted to be connected to the air intake tube of a carburetor so as to form an extension thereof and a shell IOI over whose opposite ends there are secured heads I02 and I03, respectively. The tube I00 and the shell IOI are interconnected by a tube I04 which extends through the head I02 and a partition I05 which sub-divides the interior of the shell longitudinally into a resonance chamber I06 and a cylindrical compartment. The cylindrical compartment is sub-divided into an annular compartment and a smaller cylindrical compartment by a cylindrical partition IN. The annular compartment is sub-divided longitudinally into resonance chambers I08, I 09 and I I0 by partitions III and H2 and the smaller cylindrical compartment is sub-divided longitudinally into resonance chambers H3, H4 and H5 by partitions H6 and Ill. The resonance chamber I06 and the tube I04 are interconnected by an opening H8 in the wall of the tube. The resonance chamber H3 is connected to the resonance chambers I08 and H5 by tubes H9 and I20, respectively, which extend through the partition I 01 and the partition I I6,'the resonance chamber H4 and the partition 1, respectively. The resonance chamber H4 is connected to the tube I20 and the resonance chamber I09, respectively, by an opening I2I in the wall of the tube I20 and a tube I22 which extends through the partition I0'I, respectively. The resonance chambers H0 and H5 are interconnected by a tube I23 which extends through the partition I0'I. Because of their relation to the tube I00 and to each other, the resonance chambers I06, I08, I09, H0, H3, H4 and H5 which are incorporated in the resonance unit shown in Figure 6 are to be considered, respectively, sub-primary, secondary, secondary sub-secondary, tertiary, primary, sub-secondary and secondary resonance chambers. In View of what was said in the sentence next preceding this, it will be apparent that the resonance unit shown in Figure 6 is the equivalent of a resonance unit of the type shown in Figure 2, plus (1) a resonance chamber communicating directly with the passage which interconnects the resonance chamber 30 and the passage 2325, (2) an interconnected pair of resonance chambers of which one is connected directly to the passage which interconnects one of the resonance chambers 3| and 32 with resonance chamber 30 and (3) a resonance chamber directly connected to the other of the resonance chambers 3| and 32.

Although the resonance units herein disclosed are particularly adapted for use in attenuating the sound Waves which are ordinarily transmitted through the intake manifold and carburetor of an internal combustion engine to the atmosphere, resonance units of the same type may be efiectually used to attenuate sound waves in any enclosure of finite dimensions. It willjof course, be understood that, in designing resonance units for use in any installation, it is necessary so to proportion and dimension them in the manner set forth in my co-pending application Serial No. 470,700 and the corresponding foreign patents that they will respond to the sound waves which they are intended to attenuate.

While it will be understood that effectually to attenuate the sound waves which travel through the exhaust pipe of an internal combustion engine toward the atmosphere, it is generally desirable to employ somewhat differently designed resonance units than are employed on the induction systems of such engines and that, in general, it is preferable to employ for this purpose resonance units, such as are disclosed in my copending application Serial No. 633,265 in which there are provided a greater number of resonance chambers than are necessary in resonance units which are designed for use on the induction systems of such engines, I have, for the purpose of indicating the applicability of resonance units of the type with which this application is concerned to the exhaust systems of internal combustion engines, shown in Figure 1 of the drawings the resonance unit 51 which is shown in Figure 3 of the drawings installed on the exhaust pipe I4 of the engine I0 with the projecting end 44 of the tube 43 telescopically connected with the portion of the exhaust pipe which is located on the engine side of the resonance unit,

I claim:

1. The combination, with a passage or other enclosure within which sound waves occur, of a side branch which includes a plurality of compartments which communicate with the enclosure independently of each other and intercommunicate independently of the enclosure and is so proportioned and dimensioned that it responds to and attenuates by resonance objectionable sound waves which occur within the enclosure.

2. The combination, with a duct through which sound waves and gases travel, of a resonator which is arranged as a branch of the duct and is so tuned that it responds to and attenuates by resonance sound waves of a pre-selected frequency which travel through the duct, the resonator including a plurality of chambers of which two communicate with the duct independently of each other and with a third independently of the duct and each other.

3. The combination, with a duct through which gases and sound waves travel, of a resonator which is arranged as a branch of the duct and so tuned that it responds to and attenuates by resonance sound waves of a preselected frequency which travel through the duct, the resonator including a wall which encircles and is radially spaced from a portion of the duct, walls which with the duct and the first-specified wall define a compartment, and partitions which subdivide the compartment into three chambers of which two communicate restrictedly with the duct and the third independently of the duct and each other.

4. In a silencer, a duct through which sound waves may travel, a wall which encircles and is radially spaced from a portion of the duct, walls which with the duct and the first-specified wall define a compartment which encircles the duct and is without the path of travel of gases through the silencer, partitions which subdivide the com-,- partment lengthwise into chambers of.which the end chambers in a series of three communicate with the duct independently of each other, and orifices in the partitions between the intermediate and the end chambers in the series of three which connect the intermediate chamber to the end chambers.

5. The combination, with a duct through which 5 gas and sound waves travel, of a resonator which is arranged as a branch of the duct and so tuned that it responds to and attenuates by resonance sound waves of a preselected frequency which enter the duct, the resonator including a wall which encircles and is radially spaced from a portion of the duct, walls which with the duct and the first-specified wall define a compartment which encircles the duct, and a partition which subdivides the compartment lengthwise into a plurality of chambers which communicate with the duct independently of each other and with each other independently of the duct.

ERNEST E. WILSON. 

